The objective of the proposed investigation is to define the relationship between normal and malignant tumor vasculature to obtain information of potential use to cancer diagnosis and therapy in two distinct areas: (1) a study of the general characteristics of neovascularity so that manipulation of tumor blood flow can be used to increase perfusion and thus more selectively deliver tumoricidal agents (i.e. beta-emitting microspheres or chemotherapy) and diagnostic intravascular contrast agents, (2) a determination of the differences in x-ray attenuation coefficient between malignant and normal tissue using computed tomography (CT) scanning. Attempts to improve the diagnostic accuracy of CT scanning could then be systematically studied using intravascular contrast agents which could possibly be more selectively delivered to the tumor. Host organ and tumor perfusion would be studied in high (kidney), intermediate (liver, spleen, testicle), and low (muscle) perfusion organs. Using radioactive microspheres, resting, post-vasoconstrictor and post-vasodilator (prostaglandin E1, acetylcholine), perfusion can be determined for each tumor-host organ combination. Then, after selective arterial catheterization of the tumor bearing organ and the appropriate pharmacologic intervention, chemotherpy, hyperthermia or beta-emitting microspheres would be administered and animals studied against controls for therapeutic effect. Host tissue and malignant x-ray attenuation coefficients would be established during CT studies. A systematic study of intravenous and intra-arterial iodinated contrast agents (diatrizoate, metrizamide) with and without intravascular pharmacologic intervention would establish a standard against which to compare cancer-specific contrast agents (radiopague vesicles, polyvinylpyrrolidone, perfluorocarbon compounds) for their diagnostic usefulness.